1. Field of the Invention
The present invention relates to a volume control method for audio/video devices and an audio/video device using the method. More particularly, the present invention relates to a volume control method for audio/video devices and an audio/video device, capable of controlling the volume of an external audio reproduction unit by use of volume control buttons of a remote controller without a separate On-screen display (OSD) menu window when the external audio reproduction unit such as an earphone, a headset, or speakers is plugged in.
2. Description of the Related Art
In general, the audio/video (A/V) device such as a television set, a projection TV, an LCD TV, and a home theater reproduces an audio signal through built-in speakers when receiving and reproducing the broadcast signal, and the A/V device controls its volume by use of a remote controller for controlling the speakers. When a user wants to listen to a broadcast by plugging an external audio reproduction unit such as a headset or an earphone in an A/V device, he or she can not directly control the volume level for the external audio reproduction unit by using the volume control buttons of a remote controller, but controls the volume level for the external audio reproduction unit on an OSD menu window provided on the A/V device.
FIG. 1 illustrates an audio reproduction unit of a conventional A/V device, which conceptually depicts connections of speakers and an external audio reproduction unit.
The audio reproduction unit of an A/V device has an amplification unit 10 for amplifying an input audio signal, a switch 20 for switching an output of the amplification unit 10, and speakers 30. An audio signal output from the amplification unit 10 is reproduced through the speakers 30 or a headset 40. The switch 20 is built in a headphone jack constructed to generally disconnect the amplification unit 10 with the speakers 30 when the headset 40 is plugged in the A/V device. That is, when the male connector of a headset 40 is inserted into the headphone jack, the amplification unit 10 and the speakers 30 are disconnected from each other, and an audio signal output from the amplification unit 10 is applied to the headset 40. When the male connector is not inserted into the headphone jack, the output signal of the amplification unit 10 is applied only to the speakers 30. The audio reproduction unit constructed as above applies an audio signal to the speakers 30 and the headset 40 in the same signal level. In general, the speakers 30 have the impedance of 4Ω˜8Ω, whereas the headset 40 has the impedance of 16Ω˜32Ω. Accordingly, when the volume level set for the speakers 30 is applied to the headset 40, an audio signal is reproduced by the headset 40 and the speakers 30 in a different volume level. As a result, a viewer is inconvenienced not only in properly controlling the volume level whenever plugging the headset in an A/V device, but also in setting the volume level for the speakers 30 again when releasing the headset 40 from the A/V device.
FIG. 2A is a view illustrating another audio reproduction unit provided in a conventional A/V device.
The audio reproduction unit shown in FIG. 2A partially solves the problem of the audio reproduction unit shown in FIG. 1. That is, the audio reproduction unit solves the problem of separately setting the volume levels of the speakers and the headset, which is characterized in that volume values on speakers 54 and a headset 55 are stored in an electrically erasable and programmable read only memory (EEPROM) 51. A viewer sends a control signal for channel changes to the key input unit 53 by using a remote controller, and the key input unit 53 receives and applies the control signal to the processor 52, and the processor 52 responds to the control signal and controls to change channels broadcasted from a tuner. The audio reproduction unit enables a processor 52 to detect the plugging of a headset 55 into an amplification unit 50 and apply a volume value for the headset 55 to the amplification unit 50, so as to enable the amplification unit 50 to output an audio signal in a proper volume level when a viewer plugs or unplugs the headset 55 into or from the output port of the amplification unit 50. The A/V device having the audio reproduction unit stores in the EEPROM 51 the latest volume values, that is, the latest volume values for the speakers 54 and the headset 55 that a viewer sets to the A/V device.
However, even though the volume values for the headset 55 is stored in the EEPROM 51, the viewer loads a separate OSD menu window on a display unit (not shown) of the A/V device, and increases or decreases the volume value set for the headset 55 on the display unit, when the viewer wants to change the volume value.
FIG. 2B is a view illustrating a volume-setting process for the headset 55 of the A/V device of FIG. 2A.
To control the volume level for the headset 55 shown in FIG. 2A, the viewer has the OSD menu window 60 displayed on the display unit, and adjusts the volume level with an input device such as a remote controller (not shown). In the OSD menu window 60, the viewer chooses an Audio menu 61 and a headset adjustment option 62a for adjusting the volume level for a headset, and increases or decreases the volume level of the headset 55 through a volume control menu window 62b displayed on the OSD menu window 60. In controlling the volume level for the headset 55, the viewer experiences inconvenience and not-too-easy operations.